…th `useDefineForClassFields: false` (#21369)

## Summary

When `useDefineForClassFields: false` (`setPublicClassFields` assumption), the TypeScript transform moves public/TS-private field initializers into the constructor. However, private field initializers (including `accessor` backing fields from the legacy decorator transform) were left as class field declarations, causing them to execute **before** the constructor body. This broke execution order when the initializer depended on other fields that were already moved to the constructor.

**Input:**
```ts
class Hello {
    private input = { foo };
    accessor util = this.input.foo();
}
```

**Before (broken):** `this.input.foo()` runs before `this.input = { foo }`
```js
class Hello {
    constructor() { this.input = { foo }; }
    #_util_accessor_storage = this.input.foo(); // ← runs BEFORE constructor
}
```

**After (fixed):** all instance initializers in the constructor, in source order
```js
class Hello {
    constructor() {
        this.input = { foo };
        this.#_util_accessor_storage = this.input.foo();
    }
    #_util_accessor_storage;
}
```

### Approach

Matches TypeScript's [`WillHoistInitializersToConstructor`](https://github.com/microsoft/TypeScript/blob/7b8cb3bdf82f400642b73173f941335775d6f730/src/compiler/transformers/classFields.ts#L339) logic in [`shouldTransformAutoAccessorsInCurrentClass`](https://github.com/microsoft/TypeScript/blob/7b8cb3bdf82f400642b73173f941335775d6f730/src/compiler/transformers/classFields.ts#L1069-L1073):

- Pre-scan the class body to check if any non-private instance field has an initializer that will be hoisted
- When hoisting occurs, include **all** instance fields (including `#` private) in the hoisting to preserve execution order
- When no public fields are being hoisted, private fields stay as class field declarations

No changes needed to the decorator/legacy transform — the fix is entirely in `transform_class_fields`.

Fixes #21365

## Test plan

- [x] Added test fixture: `accessor-use-define-for-class-fields` (with hoisted + non-hoisted cases)
- [x] Updated `use-define-for-class-fields-without-class-properties` expected output to match TypeScript behavior
- [x] `cargo test -p oxc_transformer` — all pass
- [x] `cargo run -p oxc_transform_conformance` — no regressions, previously failing test now passes

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